scholarly journals Multi-Stroke Lightning Interaction with Wiring Harness: Experimental Tests and Modelling

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2106
Author(s):  
Kamil Filik ◽  
Sebastian Hajder ◽  
Grzegorz Masłowski
Keyword(s):  
Lightning Discharge ◽  
Measurement Data ◽  
Experimental Tests ◽  
Metal Plate ◽  
Return Stroke ◽  
Wiring Harness ◽  
Multiple Stroke ◽  
Impulse Current Generator ◽  
Cable Bundle ◽  
Impulse Current

This paper presents the obtained results of experimental tests and modelling of lightning disturbances that were propagated in a model of aircraft cable bundle and caused by multiple lightning return-strokes interactions. The work is a continuation of previous research, which was concerned mainly with the interaction of lightning discharge with a single return-stroke. The section of the cable harness arranged above the metal plate was investigated. In one of its wires, a multiple-stroke current representing indirect lightning effects was injected from an impulse current generator dedicated to avionics immunity tests. Overvoltages induced at the ends of other wires surrounded by a braided shield, as well as the influence of line parameters and shield grounding condition on the shape and level of observed transients, were examined. The computer simulation results match the measurement data with satisfactory accuracy, and therefore, the presented model can be used to estimate indirect lightning effects in the wiring harness of avionics.

Experimental Chatter Modeling of Milling Operations

2007 ◽  
Author(s):  
Giuseppe Catania ◽  
Nicolo` Mancinelli
Keyword(s):  
Ad Hoc ◽  
Dynamical Behavior ◽  
Measurement Data ◽  
Period Doubling ◽  
Experimental Tests ◽  
Cutting Parameters ◽  
Operating Conditions ◽  
Depth Of Cut ◽  
Wide Range ◽  
Excited Vibration

This study refers to the investigation on the critical operating condition occurring on high productivity milling machines, known as chatter. This phenomenon is generated by a self-excited vibration, associated with a loss of stability of the system, causing reduced productivity, poor surface finish and noise. This study consists of the theoretical and experimental modeling of machining chatter conditions, in order to develop a real-time monitoring system able to diagnose the occurrence of chatter in advance and to dynamically modify the cutting parameters for process optimization. A prototype NC 3-axis milling machine was ad hoc realized to accomplish this task. The machine was instrumented by a dynamometer table, and a series of accelerometer sensors were mounted in the proximity of the tool spindle and the workpiece. An analytical model was developed, taking into account the periodic cutting force arising during interrupted cutting operation in milling. The system dynamical behavior was described by means of a set of delay differential equations with periodic coefficients. The stability of this system was analyzed by the semi discretization approach based on the Floquet theory. Lobe stability charts were evaluated and associated with frequency diagrams. Two chatter types were analytically and experimentally detected: period-doubling bifurcations and secondary Hopf bifurcations. Measurement data were acquired and analyzed in the time and frequency domain. Several tests were conducted in a wide range of operating conditions, such as radial immersion, depth of cut and spindle speeds and using different tools. Results are reported showing agreement between the numerical analysis and the related experimental tests.

The changes on physical characteristics of lightning discharge plasma during individual return stroke process

2014 ◽  
Vol 21 (3) ◽  
pp. 033512 ◽  
Author(s):  
He Xu ◽  
Ping Yuan ◽  
Jian-Yong Cen ◽  
Guang-Shu Zhang
Keyword(s):  
Discharge Plasma ◽  
Lightning Discharge ◽  
Physical Characteristics ◽  
Return Stroke

Dynamics of Lightning Discharge During Return Stroke

2009 ◽  
Vol 37 (1) ◽  
pp. 4-14 ◽  
Author(s):  
Jovan Cvetic ◽  
Predrag Osmokrovic
Keyword(s):  
Lightning Discharge ◽  
Return Stroke

scholarly journals Uso del procesamiento digital de imágenes para la extracción de datos de medidas experimentales publicados en formato gráfico

2019 ◽  
pp. 6-16
Author(s):  
Edebaldo Peza-Ortiz ◽  
José Bernardo Torres-Valle ◽  
Enrique García-Trinidad ◽  
Alma Delia González Ramos-Gora
Keyword(s):  
Technological Development ◽  
Data Extraction ◽  
Measurement Data ◽  
Main Tool ◽  
Experimental Tests ◽  
Laboratory Equipment ◽  
Strain Behavior ◽  
Wide Range ◽  
Pixel Grouping ◽  
Mathematical Operations

In this article, we propose a method as an alternative to obtain experimental measurement data, in the absence of laboratory equipment to perform tests, in a suitable format to perform mathematical operations in order to use them as information to validate: hypotheses, models constitutive and / or research theories focused on technological development. The proposed method uses as a main tool the image segmentation technique by region growth by pixel grouping and the normalization of the coordinates of the positions of the pixels extracted to the axis scale in the corresponding figure. The segmentation of the image separates the coordinates of the pixels that form the axes and the curves, the coordinates of the pixels of the curves are normalized to the scale of the axes. The method is tested with images of the result of experimental tests of stress-strain behavior recovered from [1]. The results of the data extraction are plotted and the averages of each curve extracted as well as the standard deviation are obtained. It is verified that the data obtained can be used to corroborate or support hypotheses in a wide range of investigations.

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